1. Field of the Invention
This invention relates to the field of plumbing. More specifically the invention comprises an assembly for joining two plumbing components without the use of adhesives.
2. Description of the Related Art
Poly vinyl chloride (“PVC”) piping and plumbing components have become increasingly common in recent years. Such components are typically joined using an adhesive (“PVC cement”). FIG. 1 shows a typical assembly in the prior art. The installation requires that two plumbing components (in this example two pipes 10) be joined together. Coupler 12 is used for this purpose. Coupler 12 includes inner diameter 14, which is sized to be a close sliding fit over the outer diameter of each of the two pipes 10. The mating surfaces are typically cleaned and primed, then coated with PVC cement. The two pipes are then slipped into coupler 12. The coupler often has an internal stop—a ring having a reduced diameter—which prevents either pipe being shoved in too far.
The PVC cement will cross-link in a matter of minutes and gain sufficient strength to hold the components together. It will continue to harden and the completed assembly is typically ready for pressurization in about one hour. Thus, the prior art components can be joined effectively using PVC cement.
This approach is not without disadvantages however. A first disadvantage is the delay involved. The installer must assemble the components and then wait to test them. This is a particular concern for a technician who is installing pool pump and filtration lines. These must be carefully spaced in order to properly locate the components they connect. As some of these lines run at 25-50 psi, the installer often must wait for the PVC cement to fully cure before testing.
In addition, prolonged exposure to PVC primers and cements can be hazardous to human health. Persons using these chemicals are cautioned to use protective gloves and masks, but many choose to ignore this safety measure. The cement can also contaminate surrounding components.
Glueless plumbing connections therefore offer advantages over the use of PVC cement. Such connections are certainly known in the art. However, these tend to operate by compressing a gasket against a flange or flare. They must generally be assembled in a predetermined order. For example, a compression nut must be slipped on a piece of piping from the end of the pipe that is distal to the joint being made, since the nut cannot pass over the flare or flange which lies next to the joint. This fact obviously limits the application of the prior art compression unions. Accordingly, a glueless plumbing union which can be assembled entirely from the end of the pipe adjacent to the joint would be desirable.